Substrate processing apparatus

ABSTRACT

The substrate processing apparatus includes a processing chamber including an outer chamber configured to hold a processing liquid and an inner chamber capable of surrounding the substrate held by the substrate holder; a liquid delivery pipe having one end coupled to a bottom of the inner chamber and other end coupled to the outer chamber; a pump configured to suck the processing liquid from the inner chamber through the liquid delivery pipe and to deliver the processing liquid to the outer chamber through the liquid delivery pipe; and a guide cover having a through-hole in which the substrate holder can be inserted. The guide cover is located below an upper end of the outer chamber and above the inner chamber.

CROSS REFERENCE TO RELATED APPLICATION

This document claims priority to U.S. Non-Provisional patent applicationSer. No. 15/076,265, filed Mar. 21, 2016 and to Japanese PatentApplication Number 2015-060284 filed Mar. 24, 2015, the entire contentsof which are hereby incorporated by reference.

BACKGROUND

FIG. 17 is a view showing a conventional substrate processing apparatus.As shown in FIG. 17, the substrate processing apparatus includes asubstrate holder 101 for holding a substrate W, and a processing chamber102 for holding a processing liquid therein. The processing chamber 102includes an inner chamber 103 in which the substrate W, held by thesubstrate holder 101, is disposed, and an outer chamber 104 surroundingthe inner chamber 103. The outer chamber 104 is coupled to the innerchamber 103 through a liquid delivery pipe 105. One end of the liquiddelivery pipe 105 is coupled to a bottom of the outer chamber 104, andother end of the liquid delivery pipe 105 is coupled to a bottom of theinner chamber 103. A pump P is coupled to the liquid delivery pipe 105.

When the pump P is operated, the processing liquid is sucked from thebottom of the outer chamber 104 through the liquid delivery pipe 105,and is supplied through the liquid delivery pipe 105 into the innerchamber 103. The processing liquid ascends in the inner chamber 103 toform an ascending flow, and overflows a side wall of the inner chamber103 into the outer chamber 104. Further, the processing liquid isreturned to the inner chamber 103 through the liquid delivery pipe 105with the operation of the pump P. In this manner, the processing liquidcirculates between the inner chamber 103 and the outer chamber 104 whileforming the ascending flow in the inner chamber 103.

In order to increase a processing rate (which is also referred to as aprocessing speed) of the substrate W, it is necessary to increase a flowvelocity of the processing liquid (i.e., a flow velocity of theprocessing liquid ascending in the inner chamber 103) which is incontact with a surface of the substrate W. However, when the flowvelocity of the processing liquid in the inner chamber 103 is increased,the processing liquid may spout from the inner chamber 103 as shown inFIG. 17, or the substrate holder 101 may be floated up by the ascendingflow of the processing liquid. Therefore, it is difficult to increasethe flow velocity of the processing liquid in the inner chamber 103.

On the other hand, when the processing liquid flows in the inner chamber103 at a low flow velocity, the processing liquid forms a laminar flowin the inner chamber 103. If the substrate W is immersed in the laminarflow of the processing liquid, the substrate W may be locally processed,and may be non-uniformly processed.

SUMMARY OF THE INVENTION

There is provided a substrate processing apparatus capable of uniformlyprocessing a substrate with an increased processing rate of thesubstrate.

Embodiments, which will be described below, relate to a substrateprocessing apparatus for processing a substrate, such as a wafer, andmore particularly to a substrate processing apparatus for processing thesubstrate by immersing the substrate in a processing liquid.

In an embodiment, there is provided a substrate processing apparatuscomprising: a substrate holder for holding a substrate; a processingchamber including an outer chamber configured to hold a processingliquid for processing the substrate, and an inner chamber housed in theouter chamber and capable of surrounding the substrate held by thesubstrate holder; a liquid delivery pipe having one end coupled to abottom of the inner chamber and other end coupled to the outer chamber;a pump coupled to the liquid delivery pipe and configured to suck theprocessing liquid from the inner chamber through the liquid deliverypipe and to deliver the processing liquid to the outer chamber throughthe liquid delivery pipe; and a guide cover having a through-hole inwhich the substrate holder can be inserted, the guide cover beinglocated below an upper end of the outer chamber and above the innerchamber.

In an embodiment, the substrate holder has a flange which closes thethrough-hole.

In an embodiment, there is provided a substrate processing apparatuscomprising: a substrate holder for holding a substrate; a processingchamber configured to hold a processing liquid for processing thesubstrate, the substrate holder being disposed in the processingchamber; processing-liquid nozzles disposed in the processing chamberand oriented to the substrate held by the substrate holder; a liquiddelivery pipe having one end coupled to a bottom of the processingchamber and other end coupled to the processing-liquid nozzles; and apump coupled to the liquid delivery pipe and configured to suck theprocessing liquid from a bottom of the processing chamber through theliquid delivery pipe and to deliver the processing liquid to theprocessing-liquid nozzles through the liquid delivery pipe.

In an embodiment, the substrate processing apparatus further comprises anozzle swing device configured to swing the processing-liquid nozzles.

In an embodiment, the substrate processing apparatus further comprises aholder oscillation device configured to cause the substrate holder toreciprocate vertically.

In an embodiment, there is provided a substrate processing apparatuscomprising: a substrate holder for holding a substrate; a processingchamber configured to hold a processing liquid for processing thesubstrate, the substrate holder being disposed in the processingchamber; a liquid delivery pipe having one end coupled to a bottom ofthe processing chamber and other end communicating with an interior ofthe processing chamber; a pump coupled to the liquid delivery pipe andconfigured to suck the processing liquid from the bottom of theprocessing chamber through the liquid delivery pipe and to return theprocessing liquid into the processing chamber through the liquiddelivery pipe; and baffle plates disposed in the inner chamber andarranged adjacent to the substrate held by the substrate holder.

In an embodiment, the substrate processing apparatus further comprises aholder oscillation device configured to cause the substrate holder tooscillate vertically.

In an embodiment, the substrate processing apparatus further comprises abaffle-plate swing device configured to swing the baffle plates.

In an embodiment, there is provided a substrate processing apparatuscomprising: a substrate holder for holding a substrate; a processingchamber configured to hold a processing liquid for processing thesubstrate, the substrate holder being disposed in the processingchamber; a liquid delivery pipe having one end coupled to a bottom ofthe processing chamber and other end communicating with an interior ofthe processing chamber; a pump coupled to the liquid delivery pipe andconfigured to suck the processing liquid from a bottom of the processingchamber through the liquid delivery pipe and to return the processingliquid into the processing chamber through the liquid delivery pipe; anda holder oscillation device configured to cause the substrate holder tooscillate vertically, the substrate holder having at least one paddlefor agitating the processing liquid.

In an embodiment, the at least one paddle comprises paddles arranged atboth sides of the substrate held by the substrate holder.

In an embodiment, the at least one paddle comprises paddles extendingacross the substrate held by the substrate holder horizontally.

In an embodiment, there is provided a substrate processing apparatuscomprising: a substrate holder for holding a substrate; a processingchamber configured to hold a processing liquid for processing thesubstrate, the substrate holder being disposed in the processingchamber; a liquid delivery pipe having one end coupled to a bottom ofthe processing chamber and other end communicating with an interior ofthe processing chamber; a pump coupled to the liquid delivery pipe andconfigured to suck the processing liquid from the bottom of theprocessing chamber through the liquid delivery pipe and to return theprocessing liquid into the processing chamber through the liquiddelivery pipe; and inert-gas supply nozzles disposed in the processingchamber and oriented to the substrate held by the substrate holder.

In an embodiment, there is provided a substrate processing apparatuscomprising: a substrate holder for holding a substrate; a processingchamber configured to hold a processing liquid for processing thesubstrate, the substrate holder being disposed in the processingchamber; a porous member secured to an upper portion of the processingchamber; a liquid delivery pipe having one end coupled to a bottom ofthe processing chamber and other end located above the porous member;and a pump coupled to the liquid delivery pipe and configured to suckthe processing liquid from the bottom of the processing chamber throughthe liquid delivery pipe and to supply the processing liquid onto theporous member through the liquid delivery pipe.

In an embodiment, there is provided a substrate processing apparatuscomprising: a substrate holder for holding a substrate; a processingchamber configured to hold a processing liquid for processing thesubstrate, the substrate holder being disposed in the processingchamber; a liquid delivery pipe having one end coupled to a bottom ofthe processing chamber and other end communicating with an interior ofthe processing chamber; a pump coupled to the liquid delivery pipe andconfigured to suck the processing liquid from the bottom of theprocessing chamber through the liquid delivery pipe and to return theprocessing liquid into the processing chamber through the liquiddelivery pipe; and an elastic membrane incorporated in a side wall ofthe processing chamber, the elastic membrane facing a surface of thesubstrate held by the substrate holder.

In an embodiment, the elastic membrane constitutes at least a part of afluid chamber which can receive a fluid therein.

According to the above-described embodiments, a descending flow of theprocessing liquid is formed in the inner chamber. Therefore, theprocessing liquid does not spout from the inner chamber, and/or thesubstrate holder is not floated when a flow velocity of the processingliquid is increased. Moreover, the processing liquid flowing at a highflow velocity form's a turbulent flow in the processing chamber, anduniformly touches the entirety of the substrate. Therefore, the entiretyof the substrate can be uniformly processed. In particular, the guidecover disposed in the processing liquid can not only smoothly guide theprocessing liquid, ascending in the outer chamber, into the innerchamber, but can also prevent a suction vortex in a surface of theprocessing liquid. As a result, the flow velocity of the processingliquid can be further increased.

Elements including the processing-liquid nozzle, the baffle plates, thepaddle, the inert-gas supply nozzle, and the porous member, have afunction to agitate the processing liquid in the processing chamber.Therefore, the processing liquid can uniformly process the entirety ofthe substrate.

When the processing liquid in the processing chamber is sucked by theoperation of the pump, a pressure of the processing liquid in theprocessing chamber is lowered. The elastic membrane deforms toward thesurface of the substrate, thereby reducing a cross section of theprocessing chamber. Therefore, the flow velocity of the processingliquid descending in the processing chamber is increased, and theprocessing liquid is brought into contact with the substrate whileforming a turbulent flow. As a result, the processing liquid canuniformly process the entirety of the substrate.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a view showing an etching apparatus according to anembodiment;

FIG. 2 is a view showing a substrate holder;

FIG. 3 is a cross-sectional view taken along line A-A in FIG. 2;

FIG. 4 is a view showing a substrate which is held in slits of eachholding arm;

FIGS. 5A, 5B, 5C are schematic views each showing a section of a surfaceof the substrate;

FIG. 6 is a view showing the etching apparatus according to anotherembodiment;

FIG. 7 is a view showing the etching apparatus according to stillanother embodiment;

FIG. 8 is a view showing a modified example of the substrate holder;

FIG. 9 is a cross-sectional view taken along line B-B of FIG. 8;

FIG. 10 is a view showing another modified example of the substrateholder;

FIG. 11 is a cross-sectional view taken along line C-C of FIG. 10;

FIG. 12 is a view showing the etching apparatus according to yet anotherembodiment;

FIG. 13 is a view showing the etching apparatus according to yet anotherembodiment;

FIG. 14 is a view showing the etching apparatus according to yet anotherembodiment;

FIG. 15 is a view showing a structural example in which elasticmembranes are provided on an inner chamber of an etching chamber;

FIG. 16 is a view showing the etching apparatus according to yet anotherembodiment; and

FIG. 17 is a view showing a conventional substrate processing apparatus.

DESCRIPTION OF EMBODIMENTS

Embodiments will be described below with reference to the drawings. InFIGS. 1 through 16, identical or corresponding elements will be denotedby the same reference numerals, and repetitive descriptions thereof areomitted.

An etching apparatus, which will be described below, is an example of asubstrate processing apparatus for processing a substrate, such as awafer. Other examples of the substrate processing apparatus include anelectroplating apparatus, an electroless plating apparatus, and anelectrolytic etching apparatus. The etching apparatus, which is oneembodiment of the substrate processing apparatus, will be describedbelow.

FIG. 1 is a view showing the etching apparatus according to anembodiment. As shown in FIG. 1, the etching apparatus includes asubstrate holder 1 for holding a substrate W, such as a wafer, and anetching chamber (or a processing chamber) 2 for holding an etchingliquid (or a processing liquid) therein for removing a resist formed ona surface of the substrate W. The etching chamber 2 includes an outerchamber 3 for holding the etching liquid therein, and an inner chamber 4surrounding the substrate W held by the substrate holder 1. The innerchamber 4 is housed in the outer chamber 3. The substrate holder 1 andthe etching chamber 2 (i.e., the outer chamber 3 and the inner chamber4) may be formed by resin material, such as PVC (polyvinyl chloride) orPTFE (polytetrafluoroethylene). Alternatively, the substrate holder 1and the etching chamber 2 may be formed by metal, such as Ti (titanium)or SUS (stainless steel), covered with resin material, such as PTFE(polytetrafluoroethylene).

The inner chamber 4 is coupled to the outer chamber 3 through a liquiddelivery pipe 10. More specifically, one end of the liquid delivery pipe10 is coupled to a bottom of the inner chamber 4, and other end of theliquid delivery pipe 10 is coupled to a bottom of the outer chamber 3. Apump P is coupled to the liquid delivery pipe 10. When the pump P isoperated, the etching liquid is sucked from the bottom of the innerchamber 4 through the liquid delivery pipe 10, and is delivered throughthe liquid delivery pipe 10 into the outer chamber 3. The etching liquidform a descending flow in the inner chamber 4 while forming an ascendingflow in the outer chamber 3.

The inner chamber 4 is completely submerged in the etching liquidcontained in the outer chamber 3. In other words, an upper end of theouter chamber 3 and a surface of the etching liquid in the outer chamber3 are located above an upper end of the inner chamber 4. If the surfaceof the etching liquid in the inner chamber 4 is located below the upperend of the inner chamber 4, the etching liquid in the outer chamber 3overflows the upper end of the inner chamber 4 into the inner chamber 4.At this time, the etching liquid involves an air, and relatively-largeair bubbles are created unevenly in the etching liquid in the innerchamber 4. Such air bubbles may prevent a uniform etching action of theetching liquid.

The etching apparatus further includes a guide cover 11 for changing adirection of the ascending flow formed in the outer chamber 3. Thisguide cover 11 is secured to an inner surface of the outer chamber 3.More specifically, the guide cover 11 is located below the upper end ofthe outer chamber 3 and below the surface of the etching liquid held inthe outer chamber 3, and above the inner chamber 4. A through-hole 11 ais formed in the guide cover 11 so that the substrate holder 1 can beinserted through the through-hole 11 a into the inner chamber 4.

The ascending flow formed in the outer chamber 3 impinges on a lowersurface of the guide cover 11, thereby changing its moving direction.The etching liquid flows through a gap between the guide cover 11 andthe inner chamber 4 into the inner chamber 4 to form the descending flowin the inner chamber 4. The etching liquid in the inner chamber 4descends along the surface of the substrate W while touching the surfaceof the substrate W held by the substrate holder 1, thereby removing aresist formed on the substrate W. The etching liquid is sucked into theliquid delivery pipe 10 coupled to the bottom of the inner chamber 4,and is delivered into the outer chamber 3 through the liquid deliverypipe 10 to form the ascending flow in the outer chamber 3. In thismanner, the etching liquid circulates between the inner chamber 4 andthe outer chamber 3 while forming the descending flow and the ascendingflow in the inner chamber 4 and the outer chamber 3, respectively. Theinner chamber 4 has a cross section which is smaller than a crosssection of the outer chamber 3. Therefore, the flow velocity of thedescending flow of the etching liquid in the inner chamber 4 is higherthan the flow velocity of the ascending flow of the etching liquid inthe outer chamber 3.

Since the descending flow of the etching liquid is formed in the innerchamber 4 and the ascending flow in the outer chamber 3 impinges on theguide cover 11, the etching liquid in the outer chamber 3 does not spoutout even if the flow velocity of the etching liquid is increased.Further, since the substrate holder 1 in the inner chamber 4 is incontact with the descending flow of the etching liquid, the substrateholder 1, which holds the substrate W, is not floated.

Without the guide cover 11, the liquid surface lying above the innerchamber 4 may sag when the flow velocity of the etching liquid isincreased, thus locally forming a suction vortex, even if the surface ofthe etching liquid in the outer chamber 3 is higher than the upper endof the inner chamber 4. If the suction vortex reaches the surface of thesubstrate W, the suction vortex may prevent the uniform etching actionof the etching liquid. Thus, the guide cover 11 is provided, so that theetching liquid ascending in the outer chamber 3 impinges on the guidecover 11 to flow into the inner chamber 4. Therefore, the generation ofthe suction vortex is prevented.

The substrate holder 1 has a flange 12 at its upper portion. The flange12 is configured to close the through-hole 11 a when the substrateholder 1 is inserted through the through-hole 11 a of the guide cover 11into the inner chamber 4. The substrate holder 1 having the flange 12will be described below with reference to FIG. 2 and FIG. 3.

FIG. 2 is a view showing the substrate holder 1, and FIG. 3 is across-sectional view taken along line A-A in FIG. 2. The substrateholder 1 has outwardly-projecting portions 13, 13. A support arm 14extends between the projecting portions 13, 13. A transporter (notshown) is configured to transport the substrate holder 1 while holdingthe support arm 14. Two holding arms 15, 15 for holding the substrate Ware secured to the support arm 14. Each holding arm 15 has a first slit15 a, a second slit 15 b, and a third slit 15 c.

FIG. 4 is a view showing the substrate W held in the slits 15 a to 15 cof the holding arm 15. One of the holding arms 15 is shown in FIG. 4. Asshown in FIG. 4, the substrate W is held by the substrate holder 1 witha periphery of the substrate W inserted into the slits 15 a to 15 c. Asshown in FIG. 2, the substrate W is slid from a position shown by adotted line to a position shown by a solid line, so that the peripheryof the substrate W is inserted into the slits 15 a to 15 c of the twoholding arms 15, 15.

The flange 12 is secured to the two holding arms 15, 15. As shown inFIG. 1, the substrate holder 1, when holding the substrate W, isinserted through the through-hole 11 a into the inner chamber 4, untilthe flange 12 is brought into contact with the guide cover 11. Theflange 12 is a lid or cap having a horizontal lower surface. A size ofthe flange 12 is larger than a size of the through-hole 11 a of theguide cover 11. Therefore, when the flange 12 is brought into contactwith the guide cover 11, the flange 12 closes the through-hole 11 a.

The guide cover 11 and the flange 12 on the guide cover 11 are locatedbelow the surface of the etching liquid. As can be seen from FIG. 1,since the flange 12 closes the through-hole 11 a, the generation of thesuction vortex in the etching chamber 2 can be completely prevented.Further, since the descending flow of the etching liquid is formed inthe inner chamber 4 during etching of the substrate W, the flange 12 ispressed against the guide cover 11, thereby stabilizing an attitude ofthe substrate holder 1 during etching of the substrate W.

FIGS. 5A to 5C are schematic views showing a section of the surface ofthe substrate W. As shown in FIG. 5A, a conductive layer 28, such as aseed layer, is formed on a surface of a dielectric layer 27. Further, aresist 29 is formed on the conductive layer 28. A metal 30 is depositedin an opening of the resist 29. When the substrate W is immersed in theetching liquid in the etching chamber 2, the resist 29 is removed andthe conductive layer 28 is exposed, as shown in FIG. 5B. Thereafter, thesubstrate W is cleaned with a cleaning liquid. The cleaned substrate Wis then immersed in another etching liquid, until the exposed conductivelayer 28 is removed, as shown in FIG. 5C.

The etching liquid, descending in the inner chamber 4 at a high flowvelocity, is brought into contact with the substrate W while forming aturbulent flow in the inner chamber 4. The etching liquid in a state ofthe turbulent flow can uniformly touch the entirety of the resist 29.Therefore, the etching liquid can uniformly remove the resist 29 at ahigh removal rate while preventing a local removal of the resist 29. Inother words, the etching liquid can uniformly process the substrate W ata high processing rate.

FIG. 6 is a view showing the etching apparatus according to anotherembodiment. In this embodiment shown in FIG. 6, the etching chamber 2 isnot divided into the outer chamber 3 and the inner chamber 4. However,the etching chamber 2 may include the outer chamber 3 and the innerchamber 4 as with the embodiment shown in FIG. 1. The etching apparatusshown in FIG. 6 includes a plurality of etching-liquid nozzles (whichmay be referred to as processing-liquid nozzles) 16 disposed in theetching chamber 2. The etching apparatus further includes the liquiddelivery pipe 10 and the pump P coupled to the liquid delivery pipe 10.One end of the liquid delivery pipe 10 is coupled to the bottom of theetching chamber 2, and other end of the liquid delivery pipe 10 iscoupled to the etching-liquid nozzles 16. The etching-liquid nozzles 16are oriented to the substrate W held by the substrate holder 1. As shownin FIG. 6, the etching-liquid nozzles 16 may be oriented obliquelydownwardly.

The pump P sucks the etching liquid from the bottom of the etchingchamber 2 through the liquid delivery pipe 10, and delivers the etchingliquid to the etching-liquid nozzles 16 through the liquid delivery pipe10. As with the above-described embodiment, when the pump P is operated,the descending flow of the etching liquid is formed in the etchingchamber 2. Therefore, floating of the substrate holder 1 disposed in theetching chamber 2 is prevented.

The etching-liquid nozzles 16 are arranged at both sides of thesubstrate W held by the substrate holder 1, and are adjacent to thesubstrate W. In this embodiment, eight etching-liquid nozzles 16 areprovided. However, the number of etching-liquid nozzles 16 is notlimited to this embodiment. The etching-liquid nozzles 16 are coupled toa nozzle swing device 18, which is configured to swing theetching-liquid nozzles 16. The nozzle swing device 18 includes linkages18A and an actuator 18B.

When the pump P is operated, the etching liquid is sucked into theliquid delivery pipe 10 while forming the descending flow in the etchingchamber 2. Further, the etching liquid is delivered through the liquiddelivery pipe 10 to each of the etching-liquid nozzles 16, and isejected from the etching-liquid nozzles 16 toward the substrate W. Thejet of the etching liquid agitates the etching liquid which is incontact with the substrate W. Therefore, the etching liquid canuniformly touch the entirety of the resist. During processing, thenozzle swing device 18 may swing the etching-liquid nozzles 16. Theswinging motions of the etching-liquid nozzles 16 can more effectivelyagitate the etching liquid that is in contact with the substrate W.

FIG. 7 is a view showing the etching apparatus according to stillanother embodiment. Structures of this embodiment, which are the same asthose of the embodiment shown in FIG. 6, will not be describedparticularly, and their duplicate descriptions are omitted. As shown inFIG. 7, one end (or an inlet) of the liquid delivery pipe 10 is coupledto the bottom of the etching chamber 2, and other end (or an outlet) ofthe liquid delivery pipe 10 is in a communication with an interior ofthe etching chamber 2. The other end (i.e., the outlet) of the liquiddelivery pipe 10 is located slightly below the surface of the etchingliquid in the etching chamber 2, and is located above the substrate W inthe etching chamber 2. The pump P is coupled to the liquid delivery pipe10, and is configured to suck the etching liquid from the bottom of theetching chamber 2 through the liquid delivery pipe 10 and to return theetching liquid into the etching chamber 2 through the liquid deliverypipe 10.

A plurality of baffle plates 20 for agitating the etching liquid aredisposed in the etching chamber 2. These baffle plates 20 are arrangedat both sides of the substrate W held by the substrate holder 1, and areadjacent to both surfaces of the substrate W. In this embodiment, eightbaffle plates 20 are provided. However, the number of baffle plates 20is not limited to this embodiment. The etching liquid descending in theetching chamber 2 is brought into contact with the substrate W whileforming the turbulent flow upon impinging on the baffle plates 20. Theetching liquid in a state of the turbulent flow prevents the localremoval of the resist. Therefore, the resist can be uniformly removed atthe high removal rate.

The baffle plates 20 are coupled to a baffle-plate swing device 21,which is configured to swing the baffle plates 20. The baffle-plateswing device 21 includes linkages 21A and an actuator 21B. The swingingmotions of the baffle plates 20 can more effectively agitate the etchingliquid that is in contact with the substrate W.

The etching apparatus of this embodiment further includes a holderoscillation device 22 configured to cause the substrate holder 1 tooscillate vertically while the substrate W, held by the substrate holder1, is immersed in the etching liquid. The holder oscillation device 22is disposed above the etching chamber 2, and is coupled to the upperportion of the substrate holder 1. When the substrate holder 1 is forcedto oscillate in the vertical directions, the etching liquid in a stateof the turbulent flow can uniformly touch the entirety of the substrateW.

FIG. 8 is a view showing a modified example of the substrate holder 1.FIG. 9 is a cross-sectional view taken along line B-B of FIG. 8. Asshown in FIG. 8 and FIG. 9, the substrate holder 1 may have a pluralityof paddles 25 for agitating the etching liquid in the etching chamber 2.Each paddle 25 comprises a horizontal plate. The paddles 25 are securedto the holding arms 15, and are arranged at both sides of the substrateW held by the substrate holder 1. In FIG. 8, the substrate holder 1 hassix paddles 25. However, the number of paddles 25 is not limited to thisembodiment. When the substrate holder 1 oscillates upward and downwardby the holder oscillation device 22, each of the paddles 25 can agitatethe etching liquid.

FIG. 10 is a view showing another modified example of the substrateholder 1. FIG. 11 is a cross-sectional view taken along line C-C of FIG.10. As shown in FIG. 10 and FIG. 11, a plurality of paddles 26,extending between the holding arms 15, 15, may be provided. The paddles26 shown in FIG. 10 and FIG. 11 extend horizontally across the substrateW held by the substrate holder 1. In FIG. 10, the substrate holder 1 hasthree paddles 26. However, the number of paddles 26 is not limited tothis embodiment.

FIG. 12 is a view showing the etching apparatus according to yet anotherembodiment. Structures of this embodiment, which are the same as thoseof the embodiment shown in FIG. 7, will not be described particularly,and their duplicate descriptions are omitted. As shown in FIG. 12, theetching apparatus includes a plurality of inert-gas supply nozzles 32disposed in the etching chamber 2. These inert-gas supply nozzles 32 arecoupled to an inert gas supply pipe 31. In this embodiment, eightinert-gas supply nozzles 32 are disposed. However, the number ofinert-gas supply nozzles 32 is not limited to this embodiment.

Each of the inert-gas supply nozzles 32 is adjacent to the substrate Wplaced in the etching chamber 2, and is oriented to the substrate W.When an inert gas is injected from the inert-gas supply nozzles 32 intothe etching liquid in the etching chamber 2, the inert gas forms bubblesin the etching liquid. These bubbles uniformly agitate the etchingliquid. Therefore, the etching liquid is uniformly brought into contactwith the resist of the substrate W, and can uniformly remove the resist.A nitrogen gas may be used as the inert gas.

FIG. 13 is a view showing the etching apparatus according to yet anotherembodiment. Structures of this embodiment, which are the same as thoseof the embodiment shown in FIG. 7, will not be described particularly,and their duplicate descriptions are omitted. As shown in FIG. 13, theetching apparatus includes a porous member 35 having a plurality of finethrough-holes 35 a. The porous member 35 is secured to the upper portionof the etching chamber 2. A total amount of the etching liquid isadjusted such that the surface of the etching liquid is located betweenan upper surface 35 b and a lower surface 35 c of the porous member 35.One end of the liquid delivery pipe 10 is coupled to the bottom of theetching chamber 2, and other end of the liquid delivery pipe 10 isdisposed above the porous member 35.

The etching liquid is supplied onto the porous member 35 through theliquid delivery pipe 10 by the operation of the pump P. The etchingliquid is supplied through the through-holes 35 a of the porous member35 into the etching chamber 2. When the etching liquid passes throughthe through-holes 35 a of the porous member 35, an air existing abovethe porous member 35 is involved in the etching liquid. As a result, theair is uniformly supplied into the etching liquid in the etching chamber2. The air forms fine bubbles in the etching liquid to agitate theetching liquid.

FIG. 14 is a view showing the etching apparatus according to yet anotherembodiment. Structures of this embodiment, which are the same as thoseof the embodiment shown in FIG. 7, will not be described particularly,and their duplicate descriptions are omitted. As shown in FIG. 14, theetching apparatus includes elastic membranes 40, 40 which areincorporated in both side walls 2 a, 2 a of the etching chamber 2,respectively. Each elastic membrane 40 serves as a part of the side wall2 a, and faces the surface of the substrate W held by the substrateholder 1. The elastic membranes 40, 40 are formed from a flexiblematerial, which may be a resin material, such as PTFE(polytetrafluoroethylene) or silicone rubber.

When the etching liquid in the etching chamber 2 is sucked by theoperation of the pump P, a pressure of the etching liquid in the etchingchamber 2 is lowered. As a result, as shown by imaginary lines(dot-and-dash lines) in FIG. 14, the elastic membranes 40, 40 deformtoward the surface of the substrate W, thereby reducing a cross sectionof the etching chamber 2. Therefore, the flow velocity of the etchingliquid descending in the etching chamber 2 is increased, and the etchingliquid is brought into contact with the substrate W while forming theturbulent flow.

FIG. 15 is a view showing a structural example in which the elasticmembranes 40, 40 are disposed on the inner chamber 4 of the etchingchamber 2. In this embodiment, the etching chamber 2 includes the innerchamber 4 and the outer chamber 3. The liquid delivery pipe 10 extendsfrom the bottom of the inner chamber 4 to a position below the surfaceof the etching liquid in the outer chamber 3. The elastic membranes 40,40 are incorporated in both side walls 4 a, 4 a of the inner chamber 4,respectively. Each elastic membrane 40 serves as a part of the side wall4 a, and faces the surface of the substrate W held by the substrateholder 1. One side of each elastic membrane 40 is in contact with theetching liquid in the inner chamber 4, while other side of the elasticmembrane 40 is in contact with the etching liquid in the outer chamber3.

The surface of the etching liquid in the outer chamber 3 lies at aposition higher than the surface of the etching liquid in the innerchamber 4. When the etching liquid in the inner chamber 4 flows throughthe liquid delivery pipe 10 into the outer chamber 3 by the operation ofthe pump P, the etching liquid in the outer chamber 3 overflows the sidewalls 4 a, 4 a of the inner chamber 4 into the inner chamber 4. Sincethe pressure of the etching liquid in the outer chamber 3 is higher thanthe pressure of the etching liquid in the inner chamber 4, the elasticmembranes 40, 40 deform toward the substrate W, thereby reducing thecross section of the inner chamber 4. Therefore, the flow velocity ofthe etching liquid descending in the inner chamber 4 is increased, andthe etching liquid is brought into contact with the substrate W whileforming the turbulent flow.

FIG. 16 is a view showing the etching apparatus according to yet anotherembodiment. Structures of this embodiment, which are the same as thoseof the embodiment shown in FIG. 14, will not be described particularly,and their duplicate descriptions are omitted. As shown in FIG. 16, boxes41, 41 are secured to the both side walls 2 a, 2 a of the etchingchamber 2, respectively. A fluid chamber 42 is defined in each box 41.The box 41 is disposed so as to cover an outer surface of the elasticmembrane 40, and a part of the fluid chamber 42 is constituted by theelastic membrane 40. Fluid ports 43, 43 are coupled to the boxes 41, 41,respectively. The fluid ports 43, 43 communicate with the fluid chambers42, 42, respectively. The entireties of the fluid chambers 42, 42 may beformed from the elastic membranes 40, 40, respectively, withoutproviding the boxes 41, 41.

When a fluid, such as pressurized gas, is introduced into the fluidchambers 42, 42 through the fluid ports 43, 43, pressures in the fluidchambers 42, 42 are increased. As a result, the elastic membranes 40, 40deform toward the substrate W, thereby reducing the cross section of theetching chamber 2. Therefore, the flow velocity of the etching liquiddescending in the etching chamber 2 is increased, and the etching liquidis brought into contact with the substrate W while forming the turbulentflow. The fluid that has been supplied into the fluid chambers 42, 42may be drained through the fluid ports 43, 43.

In the embodiment shown in FIG. 16, the fluid that has been introducedinto the fluid chamber 42 causes the elastic membrane 40 to deformtoward the substrate W. In one embodiment, an actuator, such as an aircylinder, may be used to deform the elastic membrane 40.

The embodiment shown in FIG. 1 can be combined with the above describedembodiments. For example, the guide cover 11 and the flange 12 shown inFIG. 1 may be incorporated in the embodiments shown in FIG. 7 and FIG.12 to FIG. 16.

While the present invention has been described with reference to theembodiments, it should be understood that the present invention is notlimited to the particular embodiments described above, and that othermodifications may be made within the technical concept of the presentinvention. The substrate processing apparatus according to the presentinvention is not limited to the above-described etching apparatus forremoving the resist formed on the surface of the substrate, and can beapplied to other apparatus using a processing liquid, such as anelectroplating apparatus, an electroless plating apparatus, and anelectrolytic etching apparatus. According to the present invention, theflow velocity of the processing liquid on the surface of the substratecan be increased. Therefore, a boundary layer on the substrate surfacecan be made thin, and as a result, a reaction can be accelerated. Inaddition, the higher flow velocity of the processing liquid can preventthe bubbles from adhering to the substrate.

What is claimed is:
 1. A substrate processing apparatus comprising: asubstrate holder for holding a substrate; a processing chamberconfigured to hold a processing liquid for processing the substrate, thesubstrate holder being disposed in the processing chamber; a porousmember secured to an upper portion of the processing chamber, the porousmember having an upper surface and a lower surface, the porous memberlocating a surface of the processing liquid between the upper surfaceand the lower surface of the porous member; a liquid delivery pipehaving one end coupled to a bottom of the processing chamber and otherend located above the porous member; and a pump coupled to the liquiddelivery pipe and configured to suck the processing liquid from thebottom of the processing chamber through the liquid delivery pipe and tosupply the processing liquid onto the porous member through the liquiddelivery pipe, wherein the pump supplies the processing liquid onto theporous member until the surface of the processing liquid is locatedbetween the upper surface and the lower surface of the porous member. 2.The substrate processing apparatus according to claim 1, wherein theporous member has a hole to pass the substrate holder.
 3. The substrateprocessing apparatus according to claim 1, wherein the other end of theliquid delivery pipe is branched on both sides of the substrate held bythe substrate holder.